iPhone 7 & 7 Plus seen edging out iPhone 6s lineup in US to become Apple's most-used models

Just ahead of an anticipated "iPhone 8" and "iPhone 7s/7s Plus" reveal, newly-published research shows Apple's iPhone 7 and 7 Plus are the most used iPhone models in the U.S. with a 34 percent of the install base.

Of an estimated 141 million units, about 48 million are iPhone 7/7 Plus models, Consumer Intelligence Research Partners said on Thursday. That's barely ahead of the 47 million iPhone 6s and 6s Plus units in circulation.

About 39 million iPhone 6/6 Plus models are thought to be in use. Those devices were Apple's first phones to break past the 4-inch screen size barrier, and in fact the company recently put out a 32-gigabyte iPhone 6, presumably hoping to lure people who want a "cheap" iPhone without the small screen size of the iPhone SE.

The SE has seen its install base gradually expand to 6 percent over the past year, CIRP noted. "Plus" models are also taking up a larger share, collectively sitting at 38 percent now versus 29 percent a year ago. The overall U.S. iPhone base is up from 124 million units in June 2016.

The "iPhone 8", due sometime this fall, should feature an edge-to-edge OLED screen, facial recognition, wireless charging and other upgrades such as "SmartCam" technology. The "7s" and "7s Plus" are forecast to stick to 4.7- and 5.5-inch LCD panels, but carry over some other "8 series" advancements, like wireless charging and faster processors.